Means for correlating drill bit sharpening and gauging mechanism



Jan. 16. 1945. J. F. M CARTHY, JR 2,367,229

MEANS-FOR CORRELATING DRILL BIT SHARPENING AND GAUGING MECHANISM Filed Oct. 14, 1942 s Sheets-Sheet 1 JAMESFM GARTM; JR.

INVENTOR Jan. 16, 1945. J MCCARTHY, JR 2,367,229

MEANS FOR CORRELATING DRILL BIT SHARPENING AND GAUGING MECHANISM 'Filed Oct. 14, 1942 3 Sheets-Sheet 2 JAMESF MGUAI-PTHX JR lNJENTOR BY Y ' ATTORNEYS Jan. 16, 1945. ,J, MCCARTHY, JR 2,367,229

MEANS FOR CORRELATING DRILL BIT SHARPENING AND GAUGING MECHANISM Filed Oct. 14 1942 s Sheets-Sheet 5 JAMES F M GAWHY, JR

NVENTOR Patented Jan. 16, 1945 1 UNITED STATES PATENT OFFICE 'MEANS ron eoit fiimo DRILL Brr I 'SHARPENING NISM GAUGING "MECHA- James F. ,McCarthy, Jrj., Wallace,- ,Idaho Application: October 14, 1942, f Serial N0.- 461;965

5Claims. (CLBQ-lfi) My'inventionrelates'to improvements in means for correlating drillbit sharpening and gauging mechanism, "and more particularly to machinery ofthe type used to recondition dulled detachable rock drill bits by theknown "hot-milling processes of the art. i

As shown in -'my earlier Patent No. 2,268,714,

can 'be obviated without 'difliculty and with a subsequent material enlargement of 'the utility and operability of the whole --mechanism.'

"The problemwhich I'here solve actually arises in thebits i to be-sharpelnedand*gauged. Rock drill 1 bits comprise the shape of" a=hollow'-cylindrical shank, usually internally threaded for attachment to a drill bar, having a plurality of flaring wings that are angular-1y disposed to each other and overhang the cylindrical shank. The impact faces of these wings are provided with cutting edges that extend "radially- 0f the bit and terminate on-the' outer end 'ofthe wings, the face of which is 'arcuate and has "a rearwardly decreasing taper topermit disposal of rock cuttings fromthe cutting face during the drilling operation. When a bit is-usedthe cutting-edges dull and'the taper on 'the-end of the wings-is to be adjusted to these'conditions. "It is also important thatthe adjusting operations of the sharpening and. the gauging means be tied togetherin their adjustments sothat the altering of'the operationrone is translated into asimilar "and correlated altering of the operationof the, other. To the solution of these problems my=inventi0n particularly-pertains.

' Having in mind the defects of the prior art bit conditioning mechanism, it is animportant object of this invention to provide machinery for reconditioning rock drillbits which is easily adjusted to meet varying conditionsresulting from the necessity "of conditioning i bits in various stages of their useful life.

Another objector my'invention is the provi sion, in machinery of the type described, of apparatusnfor correlating the adjustment of the elements of the reconditioning mechanism,

which apparatus operates automatically to set the mechanism although the adjustment action may be .a'ppliedto only one element of the conditions being accommodated.

A still further and more specific object-of-my inventionisyto provide,-in=.machinery of the class described, a link: mechanism between the sharpening and gauging means whereby, when the sharpening means is set toiproperly sharpen a drill,:the gau ging means, :through the action of the link mechanism will be". set to properly gauge the same drill bit.

- The qforegoingiobjects and others ancillary thereto I prefer to accomplish as follows:

altered or destroyed. Consequently a'reconditioning ofsuch a dulled bit entails the "formation of new cutting edges on-the-wingsand-the resurfacingof the gaugesendsof the wings. iEa-ch time that a bit is reconditioned it loses height andsdecreases in thecradial dimensioniofrthebit 1 Wings. 11; follows,therefore,;that-iin -the later stages of a'series of reconditionings not-only must the slope of the bit'tooth be :altered'to prevent toogreat a removal of body metaLbutsthe. angle of undercution-the endoflthe wings ofthenbit must bev more .erect .or m ore nearly;.parallel.to the axis of the bitto prevent weakeningbfthe threaded skirtif the.,-gauging device is permitted to-remove metal therefrom. .Sincethebits decrease inndiameter somewhat in proportion .to their decreasejin height it is important that mechanism for reconditioning them .be adapted I According to.-.a preferred embodiment of my invention, cImount a pair of .millingcutters in the path described byth swinging movement of a. -edrill-wbit ethat is carried upon a, pivoted arm,

tool holder. .One of these milling cutters haswa pointed nose which shapes the cutting uedge and sloping sides of: adjacent drill bit teeth or wings. Inthecase of drill bits having a plurality of teeth the bit ,is presented .to the sharpening miller severaltimes .so that both sides of each toothv are surfaced and all I the. cutting edges pf thebits aresharpened. Upon-completion of ,the sharpening operation the bit is cut to a gauge diameter .by being presented to the gauging miller in its pathof swinging movement upon the-tool holder .or arm. The gauging cutterha's. aslqping surface which receives the gauge ends of the teeth and surfaces them to properlyshape thetooth, for clearance and. cutting.

.Each of. the milling cuttersis rotated by means, generally an, electric motor, that is mountedupon a suitable machine base. Since it, is highly'idesirable to be able to accommodate a multiplicity of sizes and heights of bits, the rotor means are preferably movable on their supporting bases to alter the relation of each to the other and with respect to the bit holder. I, therefore, provide means for the manual shifting of one of said rotor means and link mechanism actuated by movement of said first mentioned rotor means to shift the second rotor in correlation to the first. Since the height and gaugeof the various sizes of bits follow a definite pattern to which the rotor means can be accommodated this correlation increases the ease and speed with which the milling operations can be conducted.

A movable stop in the path of the swinging bit holder is tied into the shifting movement of the milling cutters so that a shift of them is acv 25 by a key 26.

companied by an automatic and correlated shift of the movable stop. This stop member serves to limit the amount of travel of a bit in introducing it to the sharpening milling cutter.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings, in which Figure l is a side elevational view of my bit conditioning machine, with portions omitted for convenience of illustration;

Figure 2 is a fragmentary perspective view of the stop mechanism for the bit holder;

Figure 3 is a plan view of the bit conditioning machine;

Figure 4 is a schematic side view of. the bit holder delineating its relation to the movable sharpening miller in the various positions thereof;

Figure 5 is a fragmentary view showing the relation of the bit being gauged to the gauging miller; and

Figure 6 is a fragmentary perspective view of the shiftable rotor mounting means employed in my invention.

'A drill bit sharpening and gauging machine, to overcome the defects hereinbefore. enumerated,'must have at least two distinct characteristics; it must be adjustable in the relation of its .parts to accommodate a plurality of sizes and heights of drill bits; and it also must be capable of being adjusted without recourse to highly skilled labor or highly trained mechanics.

Accordingly, a preferred embodiment of my invention, referring to Figures 1 and 3, is constituted by a machine base H which provides the rotor mounting table 12 and the upright mounting face It. Upon the table [2 I provide machine ways I4 with which is associated the slide table l5 for sliding movement in the conventional manner. Movement of the table I5 is here shown as being produced by the rotation of lead s'orew It in the lead nut 11 that is secured to table I 5. A hand Wheel l8 on the screw facilitates its manual rotation by an operator. It will be seen that rotation of the screw If by means of the handwheel will cause the table to shift in one direction or the other according to the guiding action of the ways M.

A sharpening motor is secured to table l5 and has the pointed-nose milling cutter 2| secured upon its shaft for rotation therewith upon actuation of the motor.

Also mounted upon the shelf i2 of the machine base and to one side of the travel of motor 20 is the bit or tool holder which comprises the arm 24that pivots about the axis of shaft 25. In the instant case, the arm 24 is secured to shaft Shaft 25 is journalled in suitable bearing blocks 2'1 mounted on the machine base. A hand lever 28 attached to one end of the shaft 25 permits manual rocking thereof to swing the bit holder arm in the presentation of bits thereon to the sharpening and gaugingmillers. It is to be understood that, upon the arm 24, the bit is mounted so that it is rotatable about its axis for the presentation of the various sur faces to be milled to the milling cutters of the machine.

The movement of hand lever 28 is limited, in the direction it travels, when a bit is being presented to' the miller 2|. This limitation is governed by the stop 35 that is positioned in its path. Stop 30 is here shown as a bar that is rotatably and slidably mounted in the guide 3| pivotally mounted upon standard 32 that is at tached to the machine base. The rear end of bar stop 30 is threaded and engaged in the shank of clevis, 33 and, by means of hand wheel 34, the length of bar between the clevis and the abutment end of the stop may be varied to meet operating requirements; in other words to adjust the location of the stop in the path of the hand lever. I

Once adjusted, the stop is moved in correlation to the movement of the motor 20 through the operation of a linkage which comprises rock shaft 35 mounted in bearing 36 and having lever 31 secured to, one end. Lever 3! is pinned to the clevis 33. At the end of rock shaft 35 opposite lever 31 is secured a second lever 38 having slot 39. An arm 40 carried by the motor 20 is cooperatively attached by pin 4| in slot 39 to'lever 38. Since the motor 20 slides in a fixed plane and since the shaft 35 is mounted to rock about la, fixed axis, the operation of pin 4| in slot 39 is that of a lost-motion connection to eliminate binding in the operation of the linkage system.

The miller wheel 2| is mounted at one end of the path described by the bit when the latter ismoved by the arm 24. At the other end of this arcuate path is the gauge mill wheel 44 which is here shown as being shaped like a truncated cone and has cutting teeth on the conical face whose bit contacting face portion is designated 45. To rotate miller 44, I employ motor 46, the shaft 47 of which receives and is secured to the hub of the miller.

A motor mounting plate 48 is secured on the upright mounting face I3 of the machine base and pivots about pin 49. An ear 50 on plate 48 is adapted to receive the clevis 5| to which is attached link 52 that has at its rear end clevis On or near the rear of table i2 is provided a pivot base 54 thatsupports pivot pin 55 about which rotates or swings the'lever 56. Pin 55 forms an intermediate fulcrum for lever 56'which at one end is attached to clevis 53 and at the other end has a lost-motion pivotal connection with ear 5'! on the slidable motor base 15.

Shifting movement of base 15 is translated into a correlated movement of base 48 through the above described mechanism. Assuming that base l5 ismoved in a direction that is away from handwheel l8,-the lever 56 is swung about pivot 55 and pressure is exerted'upon the link therethrough and into the machine base.

rotation of the miller wheel 44 is disposed ds more divergent fromthevertical than previously and, consequently, the bit-engaging portion of the sloping face 45 of wheel 44 is brought closer to the horizontal.

Should the base l be drawn toward hand wheel I8, the operation'of lever 56 and link 52 is to draw the motor and its shaft into a more i erect position and the bit-engaging portion of the sloping face'45 of the miller wheel 44 diverges more from the horizontal than previously. This function is schematically suggested in Figures 4 and 5 where, in solid lines, the wheels 2| and-44 are shown in a raised position and in dotted lines two of the lower positions are depicted.

The pivoted (base 48 maybe locked to the mounting face l3 of the machine base on occasion. For this purpose, I form curved slots 60 through the base plate and bolts 6| passing By having the radius of curvature of the slots coincide with the axis of the pivot 49 it is possible for the plate to swing easily when the bolts are loosened and without interference therefrom.

In the gauging operation the operator, who is normally positioned so the gauging motor is line position' f -Ffigure '4 ma sagesst the point of the solid li'nepo'sition of miller 44 infiFigure fi As thebit heights decrease the diameter diini-nishe's, the miller 2| is moved to one of the dotted line positions and "the miller M through the action of the linksystem shifts automatically to a coriresponding position of its'se'ries. Thus it can be seen that-all that an operator need do, once the machine has beenset in 'operation and the various parts properly adjusted, is to set his mill wheel 2| to the height of the bit to be sharpened and the gauge wheel will automatically be set to the proper angle for gauge cutting.

Although I have shown and described certain v specific embodiments of my invention, I am fully aware that many modificationsthereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended miller movably supported in the path of such a bit, a gauging miller movably supported in the same path, and reverse direction link means between said :sharpening miller and said gauging to his right side, draws the hand lever 28 toward him and down. At the same time the arm 24 and the bit thereon swings in like manner until 7 the faces of the bit to be surfaced on face 45 effect contact.

By means not shown here and forming no part of the present invention, but which appears in detail I in my Patent No. 2,268,714, issued January 6, 1942', and the copending patentaapplication, Serial No. 457,563, filed September 7, 1942, the bit may be clamped to the bit arm and be rotated thereon. Or this operation may be performed by rotating the bit on the arm '24 by means of tongs or like implements.

' elements. The dashed lines of the two views su gest the relative movement of the two millers for another setting and the dot-dash showings in the two figures indicate a third setting of the mill wheels.

miller whereby movement of one of said millers is translated into a correlated shift of the other miller to vary the angle of reception of the contacting faces of the millers when a bit is presented thereto. 1

2. In a drill bit sharpening and gauging machine, the combination, comprising: bit sharpening means mounted for shifting movement, bit gauging meansfimounted for shiftingmovement, means for presenting a bit to said sharpening and to said gauging means, a movable stop to limit the degree to which a bit may be presented to 3. In a drill bit sharpening and gauging ma- 7' chine, the combination, comprising: a machine base, a table slidably shiftable upon said base,- means for shifting said table on occasion, rotor means having a sharpening miller and mounted on said base, a base plate pivotally shiftable upon In the case of the reconditioning of worn rock drill bits, a use for which my invention is particularly adaptable, it is generally true that .the' height and gauge diameter of the bit decreases with each dulling. When a bit is new'and sharp its height and gauge diameter are substantially the same, although the bitteeth have the shape of wings which extend outside the cylindrical mass of the bit itself. In the early sharpenings of such bits the under cut or angle of the gauged face may be at a fairly obtuse angle from the axis of the bit, while in later sharpening the gauge face more nearly approaches parallelism with the axis, since the wings are being cut away each time that the bit is sharpened and gauged. For this reason a bit that has been dulled only once and while it still has much of its original height is preferably sharpened while miller 2| is set at the solid said base, rotor meanshaving a gauging miller and mounted on said base plate, means for presenting a bit to said sharpening and gauging millers, and link means operable upon movement of said slidable table to shift said base plate about its'pivot. i

4. In a drill bit sharpening and gauging machine, the combination, comprising: a machine base, a table slidably shiftable' upon said base and supporting rotor means and a sharpening mounted to present a bit to said sharpening miller, a base plate pivotally shiftable upon said base and supporting rotor means having a gaugmiller, a. swingable bit holder arm pivotally ing miller in thepath described by a bit swung by the bit holder arm, .and link'means operable upon movement of said slidable table to shift said ening miller.

- 5. A drill bit sharpening and gauging machine, comprising: a movable bit sharpening wheel; a movable bit gauging wheel; a bit holder arm; a

pivot for swingably mounting said bit holder arm for movement in an arcuate path for presenting a bit carried thereon alternately to each of said wheels; said sharpening wheel being reciprocally movable relative said pivot while maintaining substantially constant the cutting face angle of 

